With the advent of miniature integrated and hybrid circuit designs there are continuing needs for small packaged passive electrical devices which are readily machine insertable in circuit boards or other support and mounting structures. Many minute active and passive devices have been packaged in small plastic cases known as DIP's (Dual In-Line Packages). Among the devices that have been DIP packaged for machine insertion are small ceramic capacitors. Though ceramic capacitors are suitable for many types of circuit constructions, such capacitors do possess certain detrimental characteristics. More specifically, ceramic capacitors are temperature sensitive, non-self healing, subject to capacitance derogation over a period of time, and possess the property of failing upon break down.
Rolled metallized film capacitors on the other hand are not subject to the detrimental characteristics inherent in ceramic capacitors. One of the problems confronted in the design of machine insertable rolled metallized film capacitors is the design of the terminals which permit packaging in such a fashion as to produce a device wherein the forces resulting from the machine insertion to the bond sites of the terminals are minimized. Other problem areas in the design of packaged rolled metallized film capacitors resides in the package that is moisture proof. Further, the terminal configuration must be such that upon assembly of the packaged capacitor on a circuit board, the electrical contacts to the circuit board must be confined to specific designated contact sites.
Numerous expedients have been devised to package and terminate rolled metallized film capacitors to insure moisture sealing. In these designs many terminal configurations have evolved to insure good electrical connection into electrical circuits. One containerized, rolled tin foil-insulating, ribbon-type of capacitor is shown in U.S. Pat. No. 1,900,352 to R. O. Lewis. In this patent, cupped solder-filled terminals are secured to the ends of the metallic ribbons and the terminals have offset sections which extend toward each other and rest on the rolled capacitor blank. The offset sections of the terminals run into projecting wire connection sections which extend through an insulating strip which forms the top of a wax filled container for receiving the capacitor blank.
Other examples of packaged rolled film capacitors may be found in U.S. Pat. Nos. 3,772,079 to T. J. Louzon; 3,806,766 to W. J. Fanning; 3,831,265 to T. J. Louzon et al. and 3,838,316 to D. R. Brown et al. In general, these patents relate to various expedients for packaging metallized film rolled capacitors having projecting wire-like leads that are manually insertable in conductive lined or plain holes formed in printed circuit boards.
In considering the prior art, attention is directed to the DIP packaged ceramic capacitors wherein a ceramic capacitor is placed in a mold and insulating plastic is molded about the capacitor. In this construction, terminating leads extend laterally through the sides of the molded case and then are bent to provide shoulders and normally extending electrical connection sections. Machine inserting tools have been devised for engaging the molded ceramic capacitor package and forcing the package toward a circuit board while the terminal shoulders ride in guide slots to insert the normally extending lead sections into holes formed in a circuit board. An example of this type of capacitor is sold under the name of Dip Guard by the AVX Ceramics Corporation of Myrtle Beach, S.C.